Staryu

Staryu is an enigmatic Pokemon that can effortlessly regenerate any appendage lost in battle. In "Clefairy and the Moonstone" Ash, Misty and Brock meet Seymour, a Pokemon researcher in search of the legendary Moonstone. Our heroes find the Moonstone in the hands of a cute Clefairy, but Team Rocket's Meowth steals the precious rock! Misty calls out her Staryu and, with a swift and powerful water-gun attack, Meowth ends up all wet!

First appearance: Episode 6 — "Clefairy and the Moonstone"